Title: Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb –1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. The five final states, targeting the decays H → WW*, ττ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 –1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.

Aad, G. Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector. United States: N. p.,
Web. doi:10.1016/j.physletb.2015.07.079.

@article{osti_1209821,
title = {Search for the associated production of the Higgs boson with a top quark pair in multilepton final states with the ATLAS detector},
author = {Aad, G.},
abstractNote = {A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb–1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. The five final states, targeting the decays H → WW*, ττ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1–1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.},
doi = {10.1016/j.physletb.2015.07.079},
journal = {Physics Letters. Section B},
number = C,
volume = 749,
place = {United States},
year = {2015},
month = {8}
}

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb –1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. The five final states, targeting the decays H → WW*, ττ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one light leptonmore » and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 –1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.« less

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb –1 of proton–proton collision data recorded by the ATLAS experiment at √s = 8 TeV at the Large Hadron Collider. Five final states, targeting the decays H → WW*, ττ , and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and onemore » light lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 –1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. This study shows the p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.« less

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb –1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. The five final states, targeting the decays H → WW*, τ τ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one lightmore » lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 –1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. Thus, the p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.« less

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb –1 of proton–proton collision data recorded by the ATLAS experiment at √s=8 TeV at the Large Hadron Collider. The five final states, targeting the decays H → WW*, τ τ, and ZZ*, are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one lightmore » lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt¯H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1 –1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. Thus,the p-value for compatibility with the background-only hypothesis is 1.8σ; the expectation in the presence of a Standard Model signal is 0.9σ.« less

A search for the associated production of the Higgs boson with a top quark pair is performed in multilepton final states using 20.3 fb -1 of proton-proton collision data recorded by the ATLAS experiment at s=8 TeV at the Large Hadron Collider. Five final states, targeting the decays H→WW * , ττ, and ZZ * , are examined for the presence of the Standard Model (SM) Higgs boson: two same-charge light leptons (e or μ) without a hadronically decaying τ lepton; three light leptons; two same-charge light leptons with a hadronically decaying τ lepton; four light leptons; and one lightmore » lepton and two hadronically decaying τ leptons. No significant excess of events is observed above the background expectation. The best fit for the tt-H production cross section, assuming a Higgs boson mass of 125 GeV, is 2.1-1.2+1.4 times the SM expectation, and the observed (expected) upper limit at the 95% confidence level is 4.7 (2.4) times the SM rate. The p-value for compatibility with the background-only hypothesis is 1.8σ the expectation in the presence of a Standard Model signal is 0.9σ.« less